Decided to check timing chain on my recently acquired w108 4.5l

I followed this tutorial
http://www.peachparts.com/Wikka/M117TimingChain

and it looks like my chain is stretched because I see 18 degrees on the crankshaft dial. Is that even possible??

Is there a way to check if my chain tensioner needs replacing?
Does anyone have a DIY instructions on how to replace chain guides? Which one should be replaced? Is it even possible reaching the bottom chain guides without tearing down half an engine?

P.S. My chain has JWIS logo on it. Is it original manufacturer or is it aftermarket?

You probably have 1 tooth off at the crank which accounts for 10° of the mis-timing, then 8° of actual stretch. 1 tooth off at the cam would be 20° and I have never heard of chain shrinkage

The chain guides to replace are the top half ones. 3 guides that are stationary and 1 on the tensioner. If you jumped time at the crank, I would replace the tensioner without hesitation. You won't really know until you have the new chain in but with 18° of actual stretch (which I highly doubt) your tensioner would be VERY far extended - any way to snap a pic if you want our input?

So if I were you my parts list, aside from a chain, would be the 4 rails, and a new tensioner, and MAKE SURE to bleed it down. You submerse it in oil and depress the plunger until no bubbles come out. I don't think the original chain would have marks (aside from the tristar logo), so it could be possible a ham-fisted mechanic messed up the timing on replacement.

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

Isn't M117 an interference engine? Wouldn't a skipped tooth be catastrophic to it?

Do you know if Febi/Bilstein chain tensioner any good.


Already put the valve cover back on. I'll try to get back to it today.

Thanks for the tip.

One skipped tooth would not cause death. You need to be off by probably 3 or 4 teeth at the crank I imagine, or 1-2 at the cam. That's 20+ degrees of mis-timing. There shouldn't be any issues with the Febi/Bilstein tensioner - it may even be OEM.

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

OK, made some photos.


1. Aligned passenger side bank


2. Result


3. And this is how driver side bank looks like


4. If I set it to 0 degrees this is what I get at the passenger side bank


5. and driver's side actually looks good

I would rather think you are one tooth off at the passenger camshaft. I tooth on the cam sprocket is 10 degrees, so 20 degrees at the crank. Try moving the chain one tooth and you may get the passenger camshaft 1 degree advanced, which is OK for a new timing chain. Try to see with the PO when the chain was changed.

PO? previous owner? Previous owner was pretty much a dealer.

I brain farted. Oops. Yeah, 1 tooth on the cam is 10° and 1 on the crank is 20°. I had it backwards. Your timing looks to be more than 20° off, and honestly, there isn't a single tooth of difference between your left and right cams by what I can see in the pics. Roll in a new chain using the DIY article as a guide, and check to see how far off you are - I have a hunch that with a new chain & new rails and tensioner, you'll be off by about 13° or so - on both cams - which means each cam is 1 tooth off.

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

OK, I guess I'll have to get a new chain, guides and tensioner. Better safe than sorry.
One more question. What are the offset woodruff keys for?

They are for making minor adjustments on the cam timing either + or -.

__________________
Tony H
W111 280SE 3.5 Coupe
Manual transmission

Past cars:
Porsche 914 2.0
'64 Jaguar XKE Roadster
'57 Oval Window VW
'71 Toyota Hilux Pickup Truck-Dad bought new
'73 Toyota Celica GT

One thing to point out. Always, and I mean, ALWAYS rotate the engine clockwise (viewed from the front) when you are checking timing chain stretch. If you go past your mark, go around again!

Yeah, but in what case do you do it?

If you're super-picky about it you can use them but the real point was when rebuilding an engine or redoing valves, say you need to shave down the head - this means less chain is between the cam and crank, and even moreso on the right (passenger) side. The issue you'll run into not having everything torn down & on a stand is that you won't know which key (if any) you need until everything's replaced, then you will need to undo the chain, pop off the cam, put in the key(s), etc. When I rolled my new chain in I had 3° of stretch on my original (aluminum-backed) rails. Which brings up another point / question:

I can't see your rails in your pics. Are your 3 riding rails (not the tensioner one) aluminum-backed? If so I always suggest NOT replacing them with the newer-styled plastic ones.

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

What do you guys think of of my cam sprocket condition? Should it be replaced?

Yup! That one's a "no-brainer".